Leather-stretching device.



No. 687,l77. Patenteq Nov. I9, I901.

J. CALDWELL.

LEATHER STRETCHING DEVICE.

(Application filed Nov. 30, 1900.

(No Model.)

UNITED STATES PATENT OFFICE.

JOHN CALDWELL, OF MINNEAPOLIS, MINNESOTA.

LEATHER-STRETCHING DEVICE.

SPECIFICATION forming part of Letters Patent No. 687,177, datedNovember19, 1901.

Application filed November 30, 1900. Serial No. 38,138. (No model.)

To all whom it may concern:

Be it known that I, JOHN CALDWELL, a citizen of the United States,residing at Minneapolis, in the county of Hennepin and State ofMinnesota, have invented certain new and useful Improvements inLeather-Stretching Devices, of which the following is a specification.

My invention relates to devices employed for holding leather While it isbeing stretched to adapt it for use in the manufacture of belting, andparticularly to the clamp form of leather-holders operated by cams andcamlevers for engaging short marginal portions of the end of a body ofleather; and the object of the invention is to provide for theadjustment of the cams and cam-lever connections toward or away from thejaw with which the cams engage.

My improvements are illustrated in the accompanying drawings, in which-Figure 1 shows a side elevation of a portion of the head of astretcher-frame provided with the improved clamp. Fig. 2 is a plan viewof the clamp. Fig. 3 is an elevation of the clamp viewed from the leftof Figs. 1 or 2, and Fig. 4 is a detached view of the screw and nutpivotally supporting the cam-lever.

In such drawings, 1 designates a plate upon or forming a portion of oneof the heads of a stretcher-frame, (either the fixed or the slidablehead.) The clamps may be connected to the head in any convenient way,for the means of such attachment is not a part of the present invention.I have shown, however, one mode of connection which consists inproviding the plate 1 with an opening to receive a pin 2, and thebase-plate 3 of the clamp has in its rear portion an opening 4, throughwhich the pin may be passed to a perforation in the plate 1 to hold theclamp against the strain of the tension while the leather is beingstretched.

The plate 3 of the clamp is provided with posts or standards 5 atopposite sides near its middle, and the upper plate or jaw 6 of theclamp has ears 7 for pivotally connecting it to the posts 5 by means ofa pintle 8, so that the upper jaw may be turned in vertical direction onits hinge connection while the lower plate remains in horizontalposition on the stretcher-head. A coilspring 9 on the middle portion ofthe pintle has its opposite ends 10 and 11 bearing, respectively,against the upper and lower clamp members, thereby tending to separatethem.

The forward adjacent portions of the two clamp members have intermeshingtransverse ribs 12 for engaging the leather 13 to prevent slipping undertension. Between the ribs 12 and the hinging connection of the two clampmembers is an upright post 14, the upper portion of which isscrew-threaded and which is secured to the base member 3 and extendsupward through a suitable opening 18, somewhat wider than the post, inthe center of the movable jaw. Above this jaw is a threaded nut 15,which has pins or trunnions 16 at opposite sides, adapted to serve asthe pivotal supports for a pair of cams 17. These cams are formed on theend of or are rigidly attached to ahandle or lever 19, the partsconstituting a cam-lever by means of which the movable jaw may beoperated. A convenient way of connecting the cam-lever to the nut is toprovide slots 20 in the sides of the cams to receive the pins,so thatthelever can be readily connected or disconnected. As the nut 15 carriesthe cam-lever, it is obvious that raising or lowering it by turning iton the screw will vary the extent to which the jaw 6 will be pressedtoward the base 3 when the cams are operated. By turning the nut upwardor downward on the post 14 the clamp can readily be adapted for properlygripping leather of different thicknesses, and the nut can be turnedeasily by turning the handle 19 in lateral direction. The handle 19 mayextend forward or rearward, as indicated by full and dotted lines inFig. 2, or toward either side when operating the cams for causing theclamp to grip the leather.

I do not in this applicationwish to claim, broadly, the devices shownfor engaging the leather and for connecting the clamp to astretcher-head, such matter being reserved to be claimed in my pendingapplications, Serial No. 1,424, filed January 15, 1900; Serial No.9,199, filed March 19, 1900; Serial No. 40,215, filed March 26, 1900,and Serial No. 21,061, filed June 21, 1900.

What I claim, and desire to secure by Letters Patent, is-

1. A clamp for a leather-stretching maconstitute a fixed clamp-jaw, amovable jaw hinged thereon, a screw secured to the former jaw andextending through an opening in the latter jaw, an adjustable nutthereon provided with trunnions at its sides, and a cam-lever pivotallyconnected to said trunnions and adapted to press the movable jaw towardthe fixed jaw,substantiallyas set forth. In testimony whereof I havehereunto set my hand this 22d day of November, 1900.

JOHN CALDWELL. In presence of- P. H. GUNoKEL, A. L. WHELAN.

